The answer is the static route to 10.30.5.128/25. This is correct because the router uses the longest prefix match rule when forwarding packets, meaning it selects the route with the most specific subnet mask that contains the destination IP. Since 10.30.5.130 falls within both the 10.30.5.0/24 range (which covers .0 through .255) and the 10.30.5.128/25 range (which covers .128 through .255), the /25 prefix is longer and more specific, so it wins over the OSPF /24 route and the default /0 route. On the CCNA 200-301 v2 exam, this concept tests your understanding of how routers prioritize routes regardless of administrative distance or metric—prefix length always comes first. A common trap is assuming a default route or a less specific route will be used when a more specific one exists; remember that the router always drills down to the longest match. Memory tip: think of it like a zip code—the more digits you match, the closer you get to the exact destination.
CCNA IP Routing Practice Question
This 200-301 practice question tests your understanding of ip routing. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. A key principle to apply: the router selects the route with the longest matching prefix to forward packets to the destination IP address.. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
R1# show ip route
O 10.30.5.0/24 [110/20] via 192.0.2.2
S 10.30.5.128/25 [1/0] via 192.0.2.6
S* 0.0.0.0/0 [1/0] via 198.51.100.1
Destination being tested: 10.30.5.130
A router has a static route to 10.30.5.128/25, an OSPF route to 10.30.5.0/24, and a default route 0.0.0.0/0 in its routing table. Which route will the router use for destination 10.30.5.130?
R1# show ip route
O 10.30.5.0/24 [110/20] via 192.0.2.2
S 10.30.5.128/25 [1/0] via 192.0.2.6
S* 0.0.0.0/0 [1/0] via 198.51.100.1
Destination being tested: 10.30.5.130
A
The static route to 10.30.5.128/25
This is correct because 10.30.5.130 falls inside the more specific /25 route.
B
The OSPF route to 10.30.5.0/24
Why wrong: This is wrong because the /24 is less specific than the /25.
C
The default route
Why wrong: This is wrong because more specific matching routes exist.
D
No route, because the destination is outside all prefixes shown.
Why wrong: This is wrong because the destination clearly matches both the /24 and the /25.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The static route to 10.30.5.128/25
The router selects the route with the longest prefix match between the destination IP and the prefixes in the routing table. 10.30.5.130 matches both 10.30.5.0/24 (prefix length 24) and 10.30.5.128/25 (prefix length 25); the /25 is more specific and wins. Option D is wrong because 10.30.5.130 falls within the subnet range of 10.30.5.128/25 (hosts .129–.254), so a valid route does exist.
Key principle: The router selects the route with the longest matching prefix to forward packets to the destination IP address.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
The static route to 10.30.5.128/25
Why this is correct
This is correct because 10.30.5.130 falls inside the more specific /25 route.
Related concept
The router selects the route with the longest matching prefix to forward packets to the destination IP address.
✗
The OSPF route to 10.30.5.0/24
Why it's wrong here
This is wrong because the /24 is less specific than the /25.
When this WOULD be correct
In a scenario where the question asks which route to use for any destination within the 10.30.5.0/24 subnet, and there are no more specific routes defined, the OSPF route to 10.30.5.0/24 would be the correct answer. This could occur in a question focused on routing protocols where no other routes are available.
✗
The default route
Why it's wrong here
This is wrong because more specific matching routes exist.
When this WOULD be correct
If the question specified that the router had no specific routes configured for the destination 10.30.5.130 and only a default route was available, then the correct answer would be the default route. For example, a question could state, 'What route will be used if no specific routes exist for 10.30.5.130?'
✗
No route, because the destination is outside all prefixes shown.
Why it's wrong here
This is wrong because the destination clearly matches both the /24 and the /25.
When this WOULD be correct
In a different scenario where the routing table does not include any routes that cover the destination IP 10.30.5.130, and the only available routes are for different subnets, this option would be correct. For example, if the routing table only had a route for 10.30.6.0/24 and no other entries, then this option would apply.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓The static route to 10.30.5.128/25Correct answer▾
Why this is correct
This is correct because 10.30.5.130 falls inside the more specific /25 route.
✗The OSPF route to 10.30.5.0/24Wrong answer — click to see why▾
Why this is wrong here
This option is wrong because the OSPF route to 10.30.5.0/24 does not match the specific destination of 10.30.5.130, which falls within the subnet of the static route 10.30.5.128/25. The static route has a more specific prefix length, making it the preferred route.
★ When this WOULD be the correct answer
In a scenario where the question asks which route to use for any destination within the 10.30.5.0/24 subnet, and there are no more specific routes defined, the OSPF route to 10.30.5.0/24 would be the correct answer. This could occur in a question focused on routing protocols where no other routes are available.
Why candidates choose this
Candidates may choose this option due to familiarity with OSPF as a dynamic routing protocol, leading them to assume it would be preferred over static routes, especially if they misinterpret the specificity of the destination address.
✗The default routeWrong answer — click to see why▾
Why this is wrong here
The default route is used when no other specific routes match the destination. In this case, the static route to 10.30.5.128/25 is a more specific match for the destination 10.30.5.130, making the default route irrelevant.
★ When this WOULD be the correct answer
If the question specified that the router had no specific routes configured for the destination 10.30.5.130 and only a default route was available, then the correct answer would be the default route. For example, a question could state, 'What route will be used if no specific routes exist for 10.30.5.130?'
Why candidates choose this
Candidates may choose this option because they might assume that a default route is always a fallback option, especially if they are not fully aware of the routing table's specifics and the importance of route specificity.
✗No route, because the destination is outside all prefixes shown.Wrong answer — click to see why▾
Why this is wrong here
This option is wrong because the destination 10.30.5.130 falls within the range of the static route 10.30.5.128/25, making it reachable through that route. The statement that the destination is outside all prefixes shown is incorrect in this context.
★ When this WOULD be the correct answer
In a different scenario where the routing table does not include any routes that cover the destination IP 10.30.5.130, and the only available routes are for different subnets, this option would be correct. For example, if the routing table only had a route for 10.30.6.0/24 and no other entries, then this option would apply.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of how subnetting works, leading them to incorrectly assume that if a specific route is not explicitly listed, the destination must be unreachable. This reflects a common confusion between available routes and the actual reachability of an IP address.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
Always prioritize the longest prefix match over broader subnets or default routes.
Detailed technical explanation
How to think about this question
Routing decisions in Cisco routers rely heavily on the concept of longest prefix match, which means the router selects the route with the most specific subnet mask that matches the destination IP address. In this question, the destination IP 10.30.5.130 falls within both the 10.30.5.0/24 and 10.30.5.128/25 subnets. Since /25 has a longer prefix (more bits fixed) than /24, the router prefers the /25 route. This behavior ensures traffic is forwarded along the most precise path available, optimizing network efficiency and reducing ambiguity.
The router first matches the destination IP against all known routes in its routing table. It then compares the subnet masks of matching routes and selects the one with the longest subnet mask (highest prefix length). Static routes, OSPF routes, and default routes can all be present simultaneously, but the longest prefix match rule overrides administrative distance or metric considerations when determining which route to use for a specific destination IP. Thus, even if the OSPF route or default route exists, the static /25 route is chosen because it is more specific.
A common exam trap is to assume that dynamic routing protocols like OSPF always take precedence over static routes or that default routes are used when multiple matches exist. However, the router always uses the longest prefix match first, regardless of route source. This means a static route with a longer prefix will be preferred over a dynamic route with a shorter prefix. Practically, this ensures precise routing and avoids routing loops or suboptimal paths, which is critical in complex enterprise networks.
KKey Concepts to Remember
The router selects the route with the longest matching prefix to forward packets to the destination IP address.
Longest prefix match means a route with a more specific subnet mask (higher prefix length) is preferred over less specific routes.
Static routes can override dynamic routes if the static route has a longer prefix match for the destination IP.
Administrative distance is only considered when multiple routes have the same prefix length in the routing table.
Default routes are used only when no more specific matching routes exist for the destination IP address.
OSPF advertises routes with specific prefixes, but the router still prefers longer prefix static routes over OSPF routes with shorter prefixes.
The router compares all matching routes and chooses the one with the highest subnet mask bits to ensure precise routing.
Misunderstanding longest prefix match leads to common exam mistakes, especially confusing route source priority with prefix specificity.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
The router selects the route with the longest matching prefix to forward packets to the destination IP address.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review the router selects the route with the longest matching prefix to forward packets to the destination IP address., then practise related 200-301 questions on the same topic to reinforce the concept.
IP Routing — This question tests IP Routing — The router selects the route with the longest matching prefix to forward packets to the destination IP address..
What is the correct answer to this question?
The correct answer is: The static route to 10.30.5.128/25 — The router selects the route with the longest prefix match between the destination IP and the prefixes in the routing table. 10.30.5.130 matches both 10.30.5.0/24 (prefix length 24) and 10.30.5.128/25 (prefix length 25); the /25 is more specific and wins. Option D is wrong because 10.30.5.130 falls within the subnet range of 10.30.5.128/25 (hosts .129–.254), so a valid route does exist.
What should I do if I get this 200-301 question wrong?
Review the router selects the route with the longest matching prefix to forward packets to the destination IP address., then practise related 200-301 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
The router selects the route with the longest matching prefix to forward packets to the destination IP address.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A router has routes for 10.10.0.0/16, 10.10.20.0/24, and a default route. Which route is used for destination 10.10.20.55?
medium
A.The 10.10.0.0/16 route
B.The default route
✓ C.The 10.10.20.0/24 route
D.The router load-balances across all matching routes
Why C: The destination matches multiple routes, but the /24 is the most specific match and wins by longest prefix match.
Variation 2. A router has a default route and a specific route to 203.0.113.0/24. Which route is used for traffic to 203.0.113.25?
hard
✓ A.The specific route to 203.0.113.0/24
B.The default route
C.Both routes are always load-balanced
D.Neither route because defaults cannot coexist with specific routes
Why A: The specific route to 203.0.113.0/24 is used because it is a more specific match than the default route. In plain language, even though the default route could technically match almost anything, the router always prefers a route that more precisely describes the destination network. Since 203.0.113.25 is inside 203.0.113.0/24, that route wins under longest-prefix match.
This is one of the most basic routing-table interpretation rules. The default route remains important as a fallback, but it is not chosen when a more specific valid route exists.
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